Electronic devices, both active, such as transistors, and passive, such as resistors, are often united to form an electronic circuit by mounting them on a printed circuit (PC) card or board formed of laminates of insulating material and deposited metallic wiring layers. As the required circuits become more complex they require more (I/O) pads in order to transfer signals to the next higher level of circuitry. Simultaneously, the industry is demanding that the size of these PC boards remain the same size if not become smaller. However, the pads must be of a minimum size to provide good interface contact. Therefore to achieve this demand of industry, the number of I/O pads must be increased.
Techniques for improving I/O pad density on the sides of such printed circuit cards are known in the prior art. One such improvement used two parallel rows in which the I/O pads in one row were staggered with respect to the I/O pads in the other row. This improvement resulted in a doubling in the number of I/O pads available on the card but did not achieve the ultimate density demanded by the industry.